Electric switch having improved electrically conducting hinge structure

ABSTRACT

An electric switch comprising a switchblade movable between open and closed positions with respect to a relatively stationary contact means and supported by a hinged type conducting structure for rotational movement of the switchblade about its own longitudinal axis and pivotal movement about an axis generally perpendicular to the switchblade.

United States Patent Kuhn Jan. 9, 1973 541 ELECTRIC SWITCH HAVING 2,658,964 11 1953 Heberlein ..200/48 A 3,299,240 1/l967 Foti 200/l66 C CTURE 3,194,905 7/1965 Jewell et a1. ..200/48 A 3,366,753 1/1968 Upton, Jr ..200/48 A [75] Inventor: Edmond W. Kuhn, Pittsburgh, Pa.

Primary Examiner-H. 0. Jones [73] Assrgnee: Vl/estmghouse Electric Corporation, An0mey A' Stratum et a1 Pittsburgh, Pa.

22 Filed: Dec. 23, 1971 ABSTRACT [211 App} 211,569 An electric switch comprising a Switchblade movable between open and closed positions with respect to a relatively stationary contact means and supported by a U-S. Cl. C, A type conducting tructure for rotational m ve [51] Int. Cl. ..H01h 31/02, H0111 l/QZ ment of the witchblade about its own longitudinal [58] Field of Search ..200/ 166 C, 48 A axis and pivotal movement about an axis generally perpendicular to the Switchblade. [56] References Cited 7 Claims, 8 Drawing Figures UNITED STATES PATENTS 2,673,902 3/ 1954 Heberlein ..200/48 A l I 53 56 e3 92 114 o 0 0O 50 I IO 40 1 44 o 72 I16 42 L0 IPATENIEUJAM 9 ms SHEET 2 UP 3 WA, 2 La :55]:

7O 72 A75 FIG. 3 J76 PATENTED N 9 I973 sum 3 0F 3 l//////// /////f/ l FIG. 6

ELECTRIC SWITCH HAVING IMPROVED ELECTRICALLY CONDUCTING HINGE STRUCTURE BACKGROUND OF THE INVENTION This invention relates to the pivotal blade type of electric disconnect switch and more particularly to the hinge type electrically conducting structure and electrically conducting switchblade support structure which forms a part of such switch.

Generally, the pivotal blade type of disconnect switch includes a blade having one end pivotally attached to a fixed support mounted on a stationary insulation stack and having the other end adapted for swinging motion about the pivot to a point between the spaced jaws of fixed contacts mounted upon another insulating stack. whereupon, rotation of the blade about its longitudinal axis provides high pressure engagement with the fixed contact jaws. When the switch is to be opened, the blade is first axially rotated to effect disconnection between the jaws and the blade and, thereafter, the blade is swung to the fully opened position. To effect closing of the disconnect switch, the blade is swung between the jaws and thereafter axially rotated to effect high pressure contact between the blade and the fixed contacts. In the pivotal blade type of outdoor high voltage electric switch, there is a problem in providing a reliable electrical current path between certain relatively stationary parts of such a switch and the relatively movable parts. One area where this problem arises is in providing a reliable current path between the switchblade, which is rotatable around its longitudinal axis, and the hinge conducting member, which is not free to rotate with the switchblade.

SUMMARY OF THE INVENTION In accordance with the invention, an electric switch includes a switchblade or contact arm having one free end movable, into and out of engagement with an associated relatively stationary contact means. The switchblade has secured to the other pivotal end a generally tubular electrically conducting switchblade support means, which is rotatably supported on an electrically conducting hinge member. The electrically conducting hinge member has a generally cylindrical portion which projects axially into one end of the associated switchblade support means. The end of the cylindrical portion, of the conducting hinge member which projects into the switchblade support means, includes a threaded portion which is secured inside said switchblade support means, by engaging an internally threaded portion of the switchblade support means, to limit axial movement of the associated switchblade, with respect to the hinged member, (while permitting limited rotary movement of the switchblade, with respect to the hinged member.) One or more resilient electrically conducting members is disposed between the tubular portion of the switchblade support. means and the associated cylindrical portion of the hinged member to maintain an electrically conducting path therebetween, during all movements of the switchblade. The hinged member in turn may be pivotally supported for rotation about an axis, which is generally perpendicular to the associated switchblade.

In one embodiment of the invention, the switchblade support means comprises an electrically conducting crank member having a generally tubular portion which projects axially into the pivotal end of the associated switchblade. The switchblade is then attached rigidly to the crank member by a suitable means, such as welding, brazing or magnetic impulse swaging.

' In a second embodiment of the invention, for use on I dual metal switches, where the switchblade is aluminum and the hinge member is copper or a copper alloy, the switchblade support means comprises an aluminum crank member having a generally tubular portion which projects axially into the pivotal end of the associated switchblade. The switchblade is then attached rigidly to the crank member by suitable means, such as welding, brazing, or magneticimpulse swaging. The end of the crank member, to which the hinge member is secured, has a tubular portion, into which is press fitted a copper or copper alloy sleeve to provide a transition from aluminum to copper.

In a third. embodiment of the invention, the switchblade support means comprises an electrically conducting cylindrical insert, with an internal threaded portion, having a machined outer surface, for close fit inside the pivotal end of the switchblade, and an electrically conducting hollow crank casting with a machined inner diameter to provide a close fit over the outside diameter of the switchblade. With the parts of the switchblade support means in place, they are joined to the switchblade by suitable means, such as magnetic impulse swaging.

In a fourth embodiment of the invention, a dual metal switch, where the switchblade is aluminum and the hinge member is copper or copper alloy, the switchblade support means comprises an electrically conducting cylindrical insert, with an internal threaded portion, having a machined outer surface for close fit inside the pivotal end of the switchblade, and an electrically conducting hollow crank casting, machined to provide a close fit over the outside diameter of the switchblade. With the parts of the switchblade support means in place, they are joined to the switchblade by suitable means such as magnetic impulse swaging. A

copper or copper alloy sleeve is press fitted into the pivotal end of the switchblade to provide a transition from aluminum to copper.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects of the invention will beapparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a partial view in side elevation of a disconnecting switch structure embodying the principal features of the invention;

FIG. 2 is a top plan view of the switch structure shown in FIG.'1;

FIG. 3 is an enlarged top plan view partly in section of a portion of the switch structure shown in FIG. 1 and FIG. 4 is an enlarged view partly in side elevation and partly in section of the portion of the switch structure shown in FIG. 3;

FIG. 5 is an enlarged view of a second embodiment of the invention partly in side elevation and partly in section of the portion of the switch structure shown in FIG. 3;

FIG. 6 is an enlarged view partly in side elevation and partly in section of a third embodiment of the invention in a disconnect switch structure having a modified Switchblade support means but which is otherwise similar to the switch structure shown in FIGS. 1 and 2;

FIG. 7 is an enlarged view partly in side elevation and partly in section of a fouth embodiment of the invention in a portion of a disconnecting switch structure having a modified switchblade support means but which is otherwise similar to the switch structure shown in FIGS. 1 and 2;and

FIG. 8 is a cross sectional view along the lines VIII- VIII in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS ing material. The number of insulators required in each of the insulator stacks 32, 34 and 36 depends upon the 1 operating voltage of the electrical system for which the disconnecting switch 10 is supplied. The insulator stacks 32 and 34 may be mounted upon fixed pedestals or spacers which in turn may be secured to the top of the associated base which may be a metal channel in configuration. As described in the above-mentioned U.S. Pat. No. 3,194,905, the insulator stack 36 is mounted upon a shaft the lower end of which is rotatably mounted in a bearing which is secured to the associated base. As indicated in FIG. 2, an operating lever 37 may be secured to the shaft provided at the lower end of the insulator stack 36 to rotate the insulator stack 36, with the operating lever.37 being adapted for connection to any conventional means for operating the operating lever 37 to affect rotation of the associated shaft and the insulator stack 36 about its own longitudinal axis.

In order to positively connect the operating lever 37 and the associated rotatable insulator stack 36 to the balance of the operating mechanism, of the disconnecting switch 10- as will be described in greater detail hereinafter, a shaft 112 is secured to a flange member 113 which in turn is secured to the top of the insulator stack 36. The shaft 112 extends upward from the upper end of the insulator stack 36 to thus form an extension of the shaft, which is provided at the lower end of the insulator stack 36, to which the operating lever 37 is attached. The shaft 112 passes through an opening pr0- vided in the terminal end casting 110, which is substantially aligned with the axis of rotation of the shaft 112 and associated insulator stack 36, and has mounted at the upper end thereof a crank arm 100, which is rotatable with the shaft 112 and which extends generally transversely with respect to the axis of rotation of the shaft 112. In order to facilitate the rotation of the shaft 112, inside the opening provided in the terminal end member 110, one or more bearings may be disposed inside the opening provided in the terminal end member 1 10. It is to be noted that in a particular application the crank arm may be formed integrally with the shaft 112.

As illustrated in FIG. 1 and FIG. 2 the disconnecting switch 10 includes a generally U-shaped relatively stationary contact assembly 40 which is mounted on and secured to the top of the insulator stack 32. The stationary contact assembly 40 includes a plurality of pairs of spaced contact jaws 43 which are mounted on and interconnected by a generally U-shaped base member 41 which is formed from an electrically conducting material and which is secured to the top of the insulator stack 32. As illustrated, the contact jaws 43 may be secured to the associated base member 41 by suitable means such as bolts. A terminal pad 42, which is adapted to receive a terminal connection, may be formed integrally with the base member 41. An upwardly extending member 44' may also be formed integrally with or secured to the other side of the base member 41, to act as a stop for the movement of an associated Switchblade 50. When desired, the base member 41 may be formed from aluminum, in such a construction the contact jaws 43 are preferably formed from copper or an alloy of copper, in order to avoid the problems associated with the high resistance oxide coating that would result if the contact jaws 43 were formed from aluminum and exposed to air.

In order to provide the electrically conducting path between the stationary contact assembly 40 and the electrically conducting parts of the disconnecting switch 10, which are mounted on top of the insulator stack 34, when the disconnect switch 10 is in a closed condition, as shown in FIGS. 1 and 2, a movable Switchblade St is provided. The blade 50 is elongated in shape and includes a main body or central portion 56, which is generally tubular in configuration and which is formed from an electrically conducting material such as copper, a copper alloy, or aluminum.

The blade 50 also includes an end portion or beaver tail member 53 at its left end which is generally rectangular in cross section to provide high pressure contact areas which are adpated to engage the contact jaws 43 of the stationary contact assembly 40. The end portion 53 of the blade 50 may be formed integrally with the associated main body portion 56 or may be formed as a separate piece which is secured to the left end of the main body portion 56 by suitable means.

When the disconnecting switch 10 is to be applied at high transmission voltages a corona shield member 48 may be mounted at the left end of the end portion 53 of the Switchblade 50. More specifically, the corono shield member 48 may be generally hollow spherical in configuration and include a threaded portion which is adapted to screw into an internally threaded opening provided at the left end of the end portion 53 of the Switchblade 50. The shielding member 48 is formed from an electrically conducting material such as alu mmum.

In order to support this Switchblade 50, for rotation about its own axis and for arcuate movement about an axis which extends generally perpendicular with respect to the longitudinal axis of the blade 50, the

right end of the main body portion 56 of the blade 50 is secured to the left .end of the generally tubular switchblade support means 60 for movement therewith. More specifically, for one embodiment of the invnetion, as illustrated in FIG. 4, the switchblade support means 60 comprises a crank member 62; a tubular portion 61 of the crank member 62 projects axially i nto the right end of the main body portion 56 of the switchblade 50. The left portion 61 of the crank member 62 is secured to the right end of the main body v portion 56 of the switchblade 50 by suitable means,

such as welding or brazing as indicated at 63 or by magnetic -impulse swaging of the area at 64 in FIG. 4. Where the main body portion 56 of the switchblade 50 is formed from copper or a copper alloy, the crank member 62 is also preferably formed from copper or a copper alloy material in order to avoid galvanic corrosion at the joint between the main body portion 56 of the blade 50 and the crank member 62.

In a second embodiment of the invention, shown in FIG. 5, the main body portion 56 of the blade 50 is formed from aluminum, the crank member 62 is also preferably formed from aluminum to avoid the problem of galvanic corrosion at the joint between the respective parts. The crank housing 62 is formed to accept a copper or copper alloy sleeve 66 which is press fitted into place to provide a transition from aluminum to copper. The inner surface 68 of the crank member 62 is prepared to receive the copper sleeve 66 by removing the aluminum oxide by a' suitable vmeans, such as coating with petroleum jelly and wire brushing. The copper sleeve 66 must be designed with sufficient interference to maintain contact pressure at maximum operating temperatures but not to result in excessive stresses at minimum operating temperatures.

In order to support the crank member 62 and in turn the switchblade 50 for rotation about the common longitudinal axis of the switchblade 50, a hinge member 70 including a generally cylindrical portion 78, as shown in FIGS. 4 and 5, projects axially inside the right hand portion of the crank member 62 and is secured to the crank member 62, to substantially prevent axial movement of the switchblade 50. The end 76 of the cylindrical portions 78 is externally threaded, to engage an internally threaded portion 65 of the crank member 62, in order to provide an electrically conducting path between the blade 50 and the associated crank member 62 and the hinge member 70, and to substantially prevent axial movement of the blade 50 and the associated crank member 62 with respect to the hinge member 70 while still permitting limited rotary movement of the blade 50 and the associated crank member 62, with respect to the cylindrical portion 78 of the hinge member 70. The hinge member 70 is preferably formed from an electrically conducting material other than aluminum such as tin-plated copper or copper alloy, in order to avoid certain problems which might otherwise result, such as galvanic corrosion or other problems associated with the use of dissimilar metals in the relatively movable electrically conducting parts of the hinge member 70 and the crank member 62.

In order to facilitate rotation of the crank member 62 on the cylindrical portion 78 of the hinged member 70 a band 88 of bearing material having a low coefficient of friction, such as polytetrafluoroethylene which is sold under the trademark Teflon, may be deposited on the outer surface 75 of the inner cylindrical bearing portion 77 of the cylindrical portion 78 adjacent to the external threaded portion 76. Also, a band 90 of bearing material, such as polytetrafluoroethylene, may be deposited on the outer surface 80 of the cylindrical outer bearing portion 79 of the cylindrical portion 78.

In order to seal off the space inside the crank member 62 at the right end of the crank member 62 and to substantially prevent the entrance of moisture inside the crank member 62, which might cause galvanic corrosion between certain electrically conducting parts, a sealing member of the O-ring'type as indicated at 92 is disposed'between the right end of the crank member 62 and the outer surface of the cylindrical portion 78 of the hinged member 70, adjacent to the cylindrical outer bearing portion 79. The O-ring 92 is retained in position by an associated recess 82 provided in the hinged member 70.

It is to be noted that the hinged member 70 is preferably formed from copper or copper alloy for reasons herein explained. In order to establish a relatively high current carrying path between the crank member 62 and the cylindrical portion 78 of the hinged member 70 one or more resilient electrically conducting members 84 is disposed in the annular space between the cylindrical portion 78 of the hinged member 70 and the crank member 62. More specifically, each of the resilient conducting members 84 may comprise a resilient corrugated sheet metal electrically conducting sleeve which includes a plurality of recesses, as shown in FIG. 8, which alternately engage the cylindrical portions 78 of the hinged member 70 and the crank member 62, as described in detail in U.S. Pat. No. 3,201,535 issued Aug. 17, 1965 to Z. F. Sabol et al. and which is assigned to the same assignee as the present application. As shown in FIG. 8, each of the electrically conducting members 84 is split providing two end portions that are biased apart by means of a wedge member 86. The ridges of conducting member 84 will be biased against the cylindrical portion 78 of the hinged member 70 and the inner surface 68 of the crank member 62. The electrically conducting member 84 is preferably formed from material which has relatively high electrical conductivity with excellent spring or resilient characteristics such as phosphorous bronze, or a zirconium copper alloy. Where desired, the electrically conducting members 84 may be axially spaced from one another by a suitable spacer 87. It is important to note that the electrically conducting path which is formed between the cylindrical portion 78 of the hinged member 70 and the crank member 62 avoids the problems of galvanic corrosion since the inner surface 68 of the crank member 62 is preferably formed from copper or a copper alloy material and the cylindrical portion 78 of the hinged member 70 is also formed from a copper or copper alloy material.

It is also to be noted that the electrically conducting path which is provided between the cylindrical portion 78 of the hinged member 70 and the crank member 62 is maintained in all operating conditions of the switchblade support means 60, for any rotary movement of the switchblade support means and associated blade 50 with respect to the hinged member 70. Any space which remains inside the crank member 62 between the cylindrical portion 78 of the hinged member and the crank member 62 may be filled with a suitable grease, such as silicone grease, to

cooperate with the sealing member 92 to substantially prevent the entrance of moisture, which might otherwise promote oxidation of galvanic corrosion between the different parts of the assembly which are formed from either aluminum or copper alloys. Finally, it is to be noted that the electrically conducting path between the crank member 62 and the cylindrical portion 78 of the hinged member 70 is completely enclosed and substantially sealed, to protect the current carrying path provided from the affect of atmospheric conditions and the oxidation or galvanic corrosion that might otherwise result in such a structure due to the presence of different electrically conducting materials.

A third embodiment of the invention is shown in FIG. 6 in which a switchblade support means 60 comprises an electrically conducting cylindrical insert 12, having a machined surface 13 for close fit inside the pivotal end of the switchblade 50, and an electrically conducting hollow crank casting l6, machined to provide close fit over the outer diameter of the switchblade 50. The insert 12, which has an internally threaded portion 1 l, is positioned inside the pivotal end of the switchblade 50. The crank casting 16 is positioned around the outside of the switchblade 50. The insert 12 and the casting 16 are then rigidly joined to the switchblade 50 by a suitable means such as magnetic impulse swaging.

In a fourth embodiment of the invention, a dual metal switch shown in FIG. 7, the switchblade 50 is aluminum and the hinge member 70 is copper or copper alloy. A copper or copper alloy sleeve 18 is press fitted into the pivotal end of the switchblade 50 to provide the transition from aluminum to copper.

In order to support the switchblade support means 60 and in turn switchblade 50, for rotation about the common longitudinal axis of switchblade 50, the hinge member 70 includes a generally cylindrical portion 78 with an externally threaded end 17 as shown in FIGS. 6 and 7, which projects axially inside the switchblade support means 60 and engages the internal threaded portion 11 of the insert 12. The engagement of the cylindrical portion 78 with the insert 12 substantially prevents axial movement of the blade 50 with respect to the hinge member 70, while still permitting limited rotary motion of the blade 50 and the switchblade support means 60 with respect to the cylindrical portion 78 of the hinge member 70. In order to establish a relatively high capacity current carrying path between the cylindrical portion 78 of the hinge member 70 and the switchblade 50, one or more resilient electrically conducting members 84 is disposed in the annular space between the cylindrical portion 78 of the hinge member 70 and switchblade 50. It is important to note that the electrically conducting path which is formed between the cylindrical portion 78 of the hinge member 70 and the switchblade 50, as shown in FIG. 6, or the copper sleeve 18, as shown in FIG. 7, avoids the problems of galvanic corrosion since the moving current carrying parts are formed from copper or copper alloy material.

In order to facilitate rotation of the switchblade 50 on the cylindrical portion 78 of the hinge member 70 a band 20 of bearing material, having a low coefficient of friction, may be disposed on the outer surface of the tubular portion 78 of the hinge member 70, adjacent to the external threaded portion 17. Also, a band 22 of bearing material, having a low coefficient of friction, may be disposed on the outer surface of a cylindrical outer bearing portion 24 of the hinge member 70.

in order to seal off the space inside the right hand portion of the switchblade 50, to substantially prevent entrance of moisture into the switchblade support means 60 which might cause galvanic corrosion between certain movable electrically conducting parts, a sealing member of the O-ring type 92 is disposed between the inner surface of the right end of the switchblade 50 and the outer surface of hinge member 70, adjacent to the cylindrical outer bearing portion 79. The O-ring 92 is retained in position by an associated recess 82 provided in the hinge member 70.

It is to be noted that the hinge member is preferably formed from copper or copper alloy for reasons given. It is also to be noted that the electrically connecting path which is provided between the cylindrical portion 78 of the hinge member 70 and the switchblade 50 is maintained in all operating positions of the switchblade support member 60 during any rotary movement of the switchblade support means 60 and associated blade 50 with respect to the hinge member 70. Any space which remains inside the switchblade support means 60 between the cylindrical portion 78 of the hinge member 70 and the switchblade 50 may be filled with a suitable grease, such as silicone grease, to cooperate with the O-ring sealing member 92 to substantially prevent the entrance of moisture, which might otherwise promote oxidation or galvanic corrosion between the different parts of the assembly which are formed from either aluminum, copper or copper alloys. Finally, it is to be noted that the electrically conducting path between the switchblade 50 and the cylindrical portion 78 of the hinge member 70 is completely enclosed and substantially sealed to protect the common current carrying path provided from the effects of atmospheric conditions.

in order to support the hinge member 70 for rotation about an axis which is generally transverse or perpendicular with respect to the axis of the blade 50, and to support the blade 50 which is assembled on the hinge member 70 for arcuate movement or travel about said axis, the spaced arms 182 of the hinge support member are disposed on opposite sides of the hinge member 70, as can best be seen in H6. 2. As shown in FlG. 3, the hinge member 70 includes a pair of hinge portions 174 and 175 which project in opposite directions and are disposed generally perpendicular to the axis of the cylindrical portion 78 of the hinge member 70. The hinge member 70 is pivotally supported between the arms 182 of the hinge support frame 80, which is formed from an electrically conducting material, by the electrically conducting hinge pins or studs 72, which pass through substantially aligned openings provided in the arms 182 and the hinge portions 174 and 175 of the hinge member 70. The heads of the hinge pins 72 are removably secured to the arms 182 of the support frame 80 by suitable means. The hinge pins 72 are preferably formed from copper or copper alloy. The openings in the hinge portions 174 and 175 are partially enlarged and adapted to receive the electrically conducting members 176 which are disposed in the annular spaces between the hinge pins 72 and the inner surfaces of the openings in the hinge portion 174 and 175. Electrically conducting members 176 are provided to establish electrically conducting paths between the hinge members 70 and the hinge pins 72 and are of the same construction and are formed from the same electrically conducting materials previously described in connection with electrically conducting members 84. In order to seal off the ends of the openings in the hinge portion 174 and 175 to thereby substantially prevent the entrance of moisture or other contaminating materials the sealing members 75, which may be of the O-ring type, are disposed between the hinge pins 72 and the hinge portions 174 and 175. The sealing members 75 are retained in position by the recesses provided in the hinge pins 72, as shown in FIG. 3.

In order to provide an electrically conducting path between the hinge support member 80 and the terminal member 110, which is mounted on top of the rotatable insulator stack 36, the generally tubular electrically conducting member 85 structurally and electrically connects the hinge support member 80 and the terminal end member 110. More specifically, the hinge support member 80 includes a flange portion 83 having an opening therein which is adapted to receive the left end of the electrically conducting member 85, as best seen in FIG. 1, with the left end of the electrically conducting member 85 being secured to the flange portion 83 by suitable means, such as welding. Similarly, the terminal end member 110 also includes a flange portion 114 having an opening therein which is adapted to receive the right end of the electrically conducting member 85; the right end of the electrically conducting member is secured to the flange portion 114 by suitable means, such as welding.

When the disconnecting switch is in the closed circuit condition, shown in FIGS. 1 and 2, an electrically conducting path extends from the terminal pad 42 at the left end of the disconnecting switch 10 to terminal pad 116 at the right end of the disconnecting switch 10..

For the embodiment shown in FIG. 4 the conducting path is from the terminal pad 42 through the base member 41, the contact jaws 43, the switchblade 50, the crank member 62, the electrically conducting members 84, the hinge member 70, the electrically conducting member 176, the hinge pins 72, the hinge support member 80, the tubular member 85 and the terminal end member 110 to the terminal pad 116.

For the embodiment shown in FIGS the path is from the terminal pad 42 through the base member 41, the contact jaws 43, the switchblade 50, the crank member 62, the copper sleeve 66, the conducting members 84, the hinge member 70, the conducting member 176, the hinge pins 72, the hinge support member 80, the tubular member 85, and the terminal 110 to the terminal pad 116.

For the embodiment shown in FIG. 6 the conducting path is from the terminal pad 42 through the base member 41, the jaws 43, the switchblade 50, the conducting member 84, the hinge member 70, the conducting member 176, the hinge pins 72, the hinge support member 80, the tubular member 85, and the terminal member 110 to the terminal pad 116.

For the embodiment shown in FIG. 7 the conducting path is from the terminal pad 42 through the base member 41, the contact jaws 43, the switchblade 50, the conducting copper sleeve 18, the electrically conducting member 84, the hinge member 70, the resilient member 176, the hinge pins 72, the. hinge support member 80, the tubular member 85, and the terminal member 1 10 to the terminal'pad 116.

In order to operatively connect or mechanically couple the crank arm 100, which is mounted on or formed integral with the shaft 112 which is secured to the top of the rotatable insulator stack 36, and the switchblade support means 60, to permit movement of the switchblade 50 during opening and closing operations of the disconnecting switch 10, the disconnecting switch 10 includes an operating link 190, which is pivotally connected to the switchblade support means 60, a slip joint 192 and a universal joint 120, which operatively connects the slip joint 192 to the crank arm 100. In the disconnecting switch 10, with the blades 50 in closed position as shown in FIGS. 1 and 2, the movable contact member 53 is in engagement with the contact jaws 43 of the stationary contact assembly and the end portion of the switchblade 50 is in engagement with the blade stop 44. Under these conditions, the operating mechanism of the disconnecting switch 10, which includes the operating link 190, the slip joint structure 192, the universaljoint 120 and the crank arm 100, considered as an overtoggle mechanism, is in an overtoggle position as best shown in FIG. 2.

During an opening operation of the disconnecting switch 10 the crank arm 100 is rotated in a counterclockwise direction, as viewed in FIG. 2, the toggle mechanism of the disconnecting switch 10 moves through a dead center position to an undertoggle position, to effect opening of the disconnecting switch 10.

While opening, the switchblade 50 moves from the closed position, shown in FIG. 1, to the open position, in which the blade 50 is angularly displaced from the closed position by approximately in a clockwise direction about the axis defined by the hinge pins 72. During an opening operation of the disconnecting switch 10, the slip joint structure 192 effectively shortens the length of the operating link 190, and the crank arm starts to rotate in a counterclockwise direction about its own axis of rotation to permit the toggle mechanism, which includes the operating link and the crank arm 100, to pass through the dead center position. As the crank arm 100 rotates further towards the undertoggle position, from the dead center posi tion, the slip joint 192 effectively lengthens the operating link 190 to thereby eliminate any longitudinal pull on the operating link 190 and to transfer the force from the crank arm 100 to the operating link 190, which provides a lateral force on the switchblade support means 60, to rotate the blade 50 about its own axis, to effect a disengagement of the blade 50 from the stationary contact assembly 40. Continued counterclockwise movement of the crank arm 100 provides a longitudinal pull on the operating link 190, since the lengthening of the operating ink 190 is limited by the slip joint structure 192, and the force is transmitted to the crank member 60 to actuate movement of the switchblade 50 along with the hinge member 70 in a counterclockwise direction, about the axis defined by the hinge pins 72,

forces between the blade 50, which is rigidly connected to the switchblade support means 60, and the crank arm 100, while providing a relatively high capacity electrically conducting path between the blades 50 and the associated hinge member 70, to thereby assure the reliable operation of the disconnecting switch 10, when exposed to outdoor atmospheric conditions over extended periods of service. It is to be understood that the teachings of the invention may be applied to a disconnecting switch structure in which substantially all of the current carrying portions are formed from copper or copper alloy, or alternating most of the important electrical conducting parts may be formed from aluminum while the balance of the electrically conducting parts, in such a dual metal construction, are. preferably formed from copper or copper alloy. This arrangement does provide a novel and economical means of transferring mechanical motion and high current from the switchblade 50 to the copper hinge casting 70 and which is able to withstand a momentary current value of greater than 100,000 amperes asymmetrical.

The apparatus embodying the teaching of this invention has several advantages. For example, an electrically conducting current path is provided between a movable switchblade and associated hinge supporting parts which is protected from adverse atmospheric conditions, which might otherwise cause corrosion problems or high resistance in the current carrying joints. in addition, the disclosed disconnecting switch construction readily lends itself to the use of an aluminum part which may be combined with electrically conducting parts formed from copper or copper'alloys in a dual metal construction. ln other words the disconnecting switch construction as disclosed permits the use of aluminum in some of the current carrying parts to thus reduce the weight of the overall disconnecting switch and to reduce the load which must be carried by the supporting structure. Finally, the contact surfaces of all movable current carrying parts, and the electrically conducting parts between such movable parts, are formed from copper or copper alloys, substantially preventing the occurrence of galvanic corrosion or oxidation.

Since numerous changes may be made in the abovedescribed apparatus and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all the matter contained in the foregoing description or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense.

lclaim:

1. An electric switch comprising a relatively stationary contact member, an elongated switchblade having one free end movable between engaged and disengaged positions with respect to said stationary contact member,

- electrically conducting switchblade support means secured to the other pivotal end of said switchblade for movement therewith, said switchblade support means having a tubular end portion, electrically conducting hinge means having a generally cylindrical portion projecting axially into said tubular end portion of said switchblade support means to support said switchblade for rotation about its own axis,

resilient electrically conducting means disposed in the tubular end portion of said switchblade sup port means, between the cylindrical portion of the electrically conducting hinge means and the switchblade support means to maintain an electrically conducting path therebetween, and

hinge support means disposed to pivotally support said electrically conducting hinge means for rotation about an axis which is generally perpendicular to said switchblade. 2O 2. The combination as claimed in claim 1 wherein said cylindrical portion of said electrically conducting hinge means includes an externally threaded portion which engages an internally threaded portion of said tubular portion of said switchblade support means to limit axial movement of said switchblade with respect to said electrically conducting hinge means.

3. The combination as claimed in claim 1 wherein said switchblade support means comprises a generally tubular conducting crank member with an internal portion threaded along the longitudinal axis to engage an externally threaded portion of the cylindrical portion of said electrically conducting hinge means.

4. The combination as claimed in claim 3 wherein said electrically conducting hinge means comprises copper,

said switchblade and said crank member being made from an electrically conducting material other than copper,

a sleeve comprising copper, pressed fitted inside the tubular end of the crank member into which the cylindrical portion of the electrically conducting hinge means projects axially so that the surfaces against which said resilient electrically conducting means bears comprises copper.

5. The combination as claimed in claim 1 wherein said switchblade support means comprises an insert having an internally threaded portion and an outer diameter formed so that said insert fits snuggly inside 50 the pivotal end of the switchblade,

a generally tubular crank casting with an inner diameter formed so that said crank casting fits tightly around the pivotal end of the switchblade,

V and a'means for rigidly joining the insert and the crank casting to the switchblade when all parts are assembled.

6. The combination as claimed in claim 5 wherein said electrically conducting hinge means comprises copper,

said switchblade is made from aluminum,

a sleeve comprising copper press fitted inside the pivotal end of the switchblade so that the surfaces against which said resilient electrically conducting means bears comprises copper.

7. The combination as claimed in claim 1 wherein sealing means is disposed between said one end of said switchblade support means and said cylindrical portion of said electrically conducting hinge means. 

1. An electric switch comprising a relatively stationary contact member, an elongated switchblade having one free end movable between engaged and disengaged positions with respect to said stationary contact member, electrically conducting switchblade support means secured to the other pivotal end of said switchblade for movement therewith, said switchblade support means having a tubular end portion, electrically conducting hinge means having a generally cylindrical portion projecting axially into said tubular end portion of said switchblade support means to support said switchblade for rotation about its own axis, resilient electrically conducting means disposed in the tubular end portion of said switchblade support means, between the cylindrical portion of the electrically conducting hinge means and the switchblade support means to maintain an electrically conducting path therebetween, and hinge support means disposed to pivotally support said electrically conducting hinge means for rotation about an axis which is generally perpendicular to said switchblade.
 2. The combination as claimed in claim 1 wherein said cylindrical portion of said electrically conducting hinge means includes an externally threaded portion which engages an internally threaded portion of said tubular portion of said switchblade support means to limit axial movement of said switchblade with respect to said electrically conducting hinge means.
 3. The combination as claimed in claim 1 wherein said switchblade support means comprises a generally tubular conducting crank member with an internal portion threaded along the longitudinal axis to engage an externally threaded portion of the cylindrical portion of said electrically conducting hinge means.
 4. The combination as claimed in claim 3 wherein said electrically conducting hinge means comprises copper, said switchblade and said crank member being made from an electrically conducting material other than copper, a sleeve comprising copper, pressed fitted inside the tubular end of the crank member into which the cylindrical portion of the electrically conducting hinge means projects axially so that the surfaces against which said resilient electrically conducting means bears comprises copper.
 5. The combination as claimed in claim 1 wherein said switchblade support means comprises an insert having an internally threaded portion and an outer diameter formed so that said insert fits snuggly inside the pivotal end of the switchblade, a generally tubular crank casting with an inner diameter formed so that said crank casting fits tightly around the pivotal end of the switchblade, and a means for rigidly joining the insert and the crank casting to the switchblade when all parts are assembled.
 6. The combination as claimed in claim 5 wherein said electrically conducting hinge means comprises copper, SAID switchblade is made from aluminum, a sleeve comprising copper press fitted inside the pivotal end of the switchblade so that the surfaces against which said resilient electrically conducting means bears comprises copper.
 7. The combination as claimed in claim 1 wherein sealing means is disposed between said one end of said switchblade support means and said cylindrical portion of said electrically conducting hinge means. 